Parker 10G-46-0600-BF

12-1 Modbus Communication
AC10 Inverter
Chapter 12 Modbus Communication
12.1 General
Modbus is a serial and asynchronous communication protocol. Modbus protocol is a general
language applied to PLC and other controlling units. This protocol has defined an information
structure which can be identified and used by a controlling unit regardless of whatever network
they are transmitted.
You can read reference books or ask for the details of MODBUS from manufactures.
Modbus protocol does not require a special interface while a typical physical interface is
RS485.
NOTE: The AC10 cannot be a Modbus master.
12.2 Modbus Protocol
12.2.1 Transmission mode
Format
ASCII mode
Start
Address
Function
Data
LRC check
End
:
(0X3A)
Inverter
Address
Function
Code
Data
Length
Data
1
…
…
Data
N
High-order
byte of LRC
Low-
order
byte of
LRC
Return
(0X0D)
Line
Feed
(0X0A)
RTU mode
Start
Address
Function
Data
CRC check
End
T1-T2-T3-T4
Inverter
Address
Function
Code
N data
Low-order
byte of CRC
High-order
byte of CRC
T1-T2-T3-T4
12.2.2 ASCII Mode (F901=1)
In ASCII mode, one Byte (hexadecimal format) is expressed by two ASCII characters.
For example, 31H (hexadecimal data) includes two ASCII characters’3(33H)’,’1(31H)’.
Common characters, ASCII characters are shown in the following table:
Characters
‘0’
‘1’
‘2’
‘3’
‘4’
‘5’
‘6’
‘7’
ASCII Code
30H
31H
32H
33H
34H
35H
36H
37H
Characters
‘8’
‘9’
‘A’
‘B’
‘C’
‘D’
‘E’
‘F’
ASCII Code
38H
39H
41H
42H
43H
44H
45H
46H
12.2.3 RTU Mode (F901=2)
In RTU mode, one Byte is expressed by hexadecimal format. For example, 31H is delivered to
data packet.
12.3 Baud rate F904
Setting range: 1200, 2400, 4800, 9600, 19200, 38400, 57600